The authors deeply regret that several systematic mistakes in Eq. 8, Table 1, and Table 2 by Salsabila et al. (2021) need to be clarified as presented here: In the Γ point, whose point group is D6h, the SOC splits the highest occupied [Formula presented]level into the [Formula presented]and [Formula presented]levels and the former is lower that the latter. The previous statement led to an error in the original Eq. 8, which according to the direct product, should be written as: [Formula presented] 3.4 Silicene, germanene and stanene The author regrets in the original Table 1 that the stanene SOC band gap value should read 135 meV as the explanation in the original paper chapter 3.4 in the fourth paragraph. The corrected table is reproduced and tabulated below. 3.5 Z2 invariant We made systematic mistakes concerning two incorrect values in the original Table 2. The frequent errors are due to changing the result in the original of Eq. 8, which is the above results of the direct product in the Γ point led to the [Formula presented]level being higher than the [Formula presented]level. Thus, the values of column IR in the row of the band numbers 3 and 4 in the original articles should be replaced by [Formula presented]and [Formula presented] respectively. The corrected table is reproduced below. We evaluate the Z2 invariant v by using the identified IR of bands and confirm that v = 1 for all the materials [1,2]. The authors would like to apologise for any inconvenience caused.